KR20060057184A - Mobile terminal with improved color image displaying apparatus and method - Google Patents

Abstract

The present invention relates to a mobile communication terminal having an improved color image display device and method. In particular, the present invention provides a structure of a mapping table that is improved according to the color recognition characteristics of a human being so that color image information can be output to a display portion with a small amount of data. The present invention relates to a mobile communication terminal having an image display apparatus and method capable of implementing color images.

Color Image, Gamut, Mapping Table, Display, Human Perception

Description

A mobile communication terminal having an improved color image display device and method TECHNICAL FIELD             

1 is a view illustrating a color reproduction range of a display unit provided in a general display device having a relatively large size and a mobile communication device;

2 is a diagram illustrating an example of converting a color of an original image using a gamut mapping table;

Degree

 3a is the original image photo,

3b is a photograph showing a change in the image when the entire red, green, and blue components of the original image are compressed;

3C, 3D, and 3E are photographs showing changes in the image when the red, green, and blue components of the original image are compressed, respectively,

4 is a diagram illustrating a mapping table in consideration of human color recognition characteristics according to an embodiment of the present invention;

5 is a block diagram of a mobile communication terminal constructed according to an embodiment of the present invention;

6 is a flowchart illustrating a method of outputting color image information to a display unit using a mapping table in consideration of human color recognition characteristics according to an embodiment of the present invention;

7 is a flowchart illustrating a method of outputting color image information to a display unit by using a mapping table in consideration of human color recognition characteristics in a mobile communication terminal having a color sensor according to an exemplary embodiment of the present invention.

The present invention relates to a mobile communication terminal having an improved color image display device and method. In particular, the present invention provides a structure of an improved mapping table using a YUV method in consideration of human color recognition characteristics to provide color image information. The present invention relates to a mobile communication terminal having a color image display apparatus and method capable of realizing a color image even with a small amount of data by outputting to a display unit.

Hereinafter, the color image data, the color image information, the color information, and the color information are all used as terms having the same meaning. Also, color and color are used as terms having the same meaning.

In general, mobile communication systems have been used as a means of providing voice calls to users, but now mobile communication systems have evolved to provide various services to users, such as text messages, pictures or video services, and data such as mobile banking. It also provided a service. As a result, users have many opportunities to access various images through the display unit of the mobile communication terminal.

However, due to the difference between the color reproduction ability of the display unit and the color information of the original image, an image output to the display unit is distorted and is output. As described above, due to the limitation of colors that the display unit provided in the mobile communication terminal can express, the original color information cannot be properly represented.

Therefore, there is a need for a method of correcting the difference between the color gamut of the original image and the color reproduction capability of the display unit.

Since the color reproduction ability of the display unit is different for each display unit implemented in various types of mobile communication terminals, a mapping table is provided for each terminal to map the color information of the original image to the display unit, thereby outputting the most natural image. The table is called Gamut mapping table.

As described above, a situation in which the original color information cannot be properly represented due to the limitation of the color that can be represented by the display unit provided in the mobile communication terminal will be described with reference to FIG. 1.

1 is a diagram illustrating a color reproduction range of a display unit provided in a general display device and a mobile communication terminal having a relatively large size, such as a TV or a computer. Reference numeral 100 of FIG. 1 denotes a color reproduction range of a general display device, reference numeral 102 denotes a color reproduction range of a display unit provided in a mobile communication terminal, and reference numeral 104 may be reproduced on a display unit of the mobile communication terminal. Indicates a range of colors that do not exist. Each of R, G, and B means red, green, and blue, which are three primary colors of light.

A typical display device may represent almost all of red (hereinafter referred to as R), green (hereinafter referred to as G), and blue (hereinafter referred to as B), but may be moved as shown in FIG. Since the display unit provided in the communication terminal is smaller in size than a general display device, the color that can be implemented due to the limitation of human color perception ability is limited.

Therefore, in order to naturally implement the color information of the area corresponding to the reference numeral 104 of FIG. 1 in the display unit of the mobile communication terminal, the original image is visually reproduced on the display unit of the mobile communication terminal using a gamut mapping method. Serve The gamut mapping refers to a method of compensating for the difference between the color information of the original image and the color reproduction capability of the display unit of the mobile communication terminal. An example of such gamut mapping will be described with reference to FIG. 2.

2 illustrates an example of converting a color of an original image using a gamut mapping table. Reference numeral 200 of FIG. 2 denotes each of original image data classified into R, G, and B values, and reference numeral 202 denotes 1: 1 using data on color reproduction capability of the display apparatus. To be mapped. For example, the mobile communication terminal uses the original image data values R: 51, G: 51, and B: 0 as reference numeral 204 to the data values R: 39, G: 53, and B: 0 output on the display unit with reference numeral 206. Map and print. 2 illustrates only one example of gamut mapping, and the actual gamut mapping is applied differently according to the color reproduction ability of the display device.

Recently, with the development of display devices, mobile communication terminals are generally equipped with QVGA (Quarter Video Graphics Array) (320 pixel X 240 pixel) display devices. In addition, small display devices having a color expressing ability of more than 260,000 colors are widely used, and display devices having excellent color expressing ability can be easily seen from around.

Applying the existing gamut mapping method requires a large amount of data even in the above-described QVGA and 260,000 colors. This is described below.

The size of the gamut mapping table required to map one component composed of RGB to another component composed of RGB may be calculated as in Equation 1 below. Assume that RGB is represented by 8Bit (which has the number of 256 cases).

Table Size = 8bit × 8bit × 8bit = 2 ⁸ × 2 ⁸ × 2 ⁸ = 256 × 256 × 256

In other words, the number in this case is a power of 256 and has a value of approximately 16 million. In order to express these values, a mapping table size of 16 million (16M) is required.

If each RGB is represented by 6Bit (which has 64 cases), 2 ⁶ = 64 colors are represented and the cube of 64 is about 260,000 colors.

Until now, since a mobile communication terminal generally has a small display device and does not require accurate color reproducibility as required by a monitor, 260,000 colors may not be a problem.

However, in the future, there will be a demand for more accurate color reproduction as broadcast services such as satellite digital media broadcasting (DMB) are implemented.

Accordingly, there is a need for a mapping table having color reproducibility, which has a problem that the size becomes very large as seen above. If the size of the mapping table is very large in order to express the color, the memory shortage is caused by allocating a large portion of the memory to store the table data.

Therefore, there is a need for a method and apparatus for reducing the size of the mapping table by improving a method of mapping each of the original image data, which is being used up to now, to 1: 1 mapping using data on the color reproduction capability of the display device.

Accordingly, an object of the present invention is to provide a mobile communication terminal having an apparatus and method for displaying color image information to a user.

Another object of the present invention is to provide a mobile communication terminal including a color display device and a method having a mapping table of a small size in displaying an original color image using human color perception characteristics.                         

Another object of the present invention is a mobile communication terminal having a color sensor for considering the color information of the surrounding environment, a color display having a mapping table of a small size in displaying the original color image using the color perception characteristics of the human A mobile communication terminal including an apparatus and a method is provided.

In order to achieve the above objects, the device of the present invention considers each color information of preset red, green, and blue colors in consideration of the color perception characteristic of human being most sensitive to the green component among red, green, and blue colors. A memory for storing a gamut mapping table for determining a ratio, a color image information corresponding to the original color image of the gamut mapping table, and combining the mapped color image information And a display for visually displaying the combined color image information.

Another apparatus of the present invention for achieving the above object, the color sensor for measuring the color information and the amount of light of the surrounding environment, the color perception characteristics of the human most sensitive to the green component of the red, green, blue color information of the original color According to the gamut mapping table based on the gamut mapping table which determines the ratio of the amount of each color information of red, green and blue which are set in advance, and the color information and the light quantity information of the surrounding environment output from the color sensor. Color sensor mapping table that determines the ratio of the amount of each color information of red, green, and blue that is preset by considering color perception characteristics of human-recognized green components among red, green, and blue colors. Memory to store the original color image, the original image of the gamut table Mapping to corresponding color image information, mapping to color image information corresponding to gamut-mapped color image information according to the gamut mapping table of the color sensor mapping table, and combining the respective color image information to be mapped. And a display unit for visually displaying the combined color image information.

According to the method of the present invention for achieving the above objects, the color information of the red, green, blue color is set in advance in consideration of the color perception characteristics of the human color most sensitive to the green component of the red, green, blue, the original color image information Setting a ratio of an amount of s, mapping the original color image to color image information corresponding to the original color image, combining the mapped color image information, and outputting the combined color image information; It provides a color image display method of a mobile communication terminal, characterized in that it comprises the step of visually displaying.

Another method of the present invention for achieving the above object is, the color sensing step of measuring the color information and the amount of light of the surrounding environment, the color perception of the human most sensitive to the green component of the red, green, blue color information of the original color image Gamut mapping table setting step of setting the ratio of the amount of each color information of red, green, and blue which is set in consideration of the characteristic, mapping the gamut based on the color information and the light quantity information of the surrounding environment output from the color sensor A color that determines the ratio of the amount of each color information of red, green, and blue which is preset based on the color perception characteristic of human beings most sensitive to the green component among red, green, and blue, according to the table. In the sensor mapping table setting step, the original color image is replaced with a gait mapping table setting step. Mapping to color image information corresponding to the original image set in the first step, mapping to color image information corresponding to gamut mapped color image information according to the gait mapping table set in the color sensor mapping table setting step, and Comprising the step of combining each of the mapped color image information, and visually displaying the combined color image information provides a color image display method of a mobile communication terminal.

In addition, in order to achieve the object of the present invention, it is possible to change the above embodiments, the addition of components, and the like. In addition, other embodiments are possible.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, when it is determined that the detailed description of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

A mobile communication terminal having an image display device and method according to an embodiment of the present invention can be applied to all mobile communication terminals having a general display device as a display device. However, in the following description, a mobile phone terminal having a liquid crystal display (LCD) as a display device will be described as an example of a mobile communication terminal.

The principle of human perception of color depends on the degree of detection of the light intensity of the cell. There are many ways to express this as a quantified value.

A typical example is simply to use RGB (Red, Green, Blue) values of each color component. Colors are a combination of RGB and humans know the unique colors of the subject they want to perceive according to their strengths and weaknesses.

Another example is YUV. The YUV method is based on the fact that the human eye is more sensitive to brightness than color itself. This method distinguishes colors into Y and V components, which constitute luminance and chrominance. Like RGB, YUV is a method of expressing a specific color.

The YUV method and the RGB method both express colors, and it is known that a corresponding formula such as Equation 2 below holds for the difference between the two expression methods.

Y = 0.3R + 0.59G + 0.11B

U = (B-Y) × 0.493

V = (R-Y) × 0.877

As described above, since humans react sensitively to light, Y: U: V should not be 1: 1: 1 when representing the color information in the YUV method. .

That is, it is expressed as the weighting of Y: U: V = 4: 2: 2. That is, when the human perceives color, the brightness component is the most sensitive to Y, thereby increasing the specific gravity of Y compared to UV.

Looking at the first equation for calculating Y in Equation 2, it can be seen that the coefficient of the RGB value is different. This is because human eye cells are sensitive to green. In other words, the Y component is obtained by considering the color perception characteristic of human.

The present invention focuses on the ratio of R: G: B = 3: 6: 1 that can be obtained from the Y value of Equation 2, which is a process of converting RGB into YUV. The sensitivity of each color is determined by using compression within a range that humans cannot perceive. This determination will be described with reference to FIG. 3.

In FIG. 3, FIG. 3A is a photograph showing an original image. Figure 3b is a picture showing the change of the image when the entire red, green, blue component of the original image is compressed, Figures 3c, 3d, 3e is a case of compressing the red, green, blue component of the original image respectively It is photograph showing change of image.

Specifically, FIG. 3B is an image in which the entire channel (RGB) component of the original image is compressed to block size 10. Referring to FIG. FIG. 3C is an image in which only R component is compressed to block size 10 in FIG. 3A, and FIG. 3D is an image in which only G component is compressed to block size 10 in FIG. 3A, and FIG. 3E is only B component is compressed to block size 10 in FIG. 3A. One image.

Referring to FIG. 3, the compressed images of R, G, and B components (FIGS. 3C, 3D, and 3E) with respect to the same image, respectively, show that the compressed 3G is the most distorted. In addition, it can be seen that FIG. 3E in which B is compressed is insignificant.

As shown in Equation 2 and FIG. 3, human eye cells respond to RGB in the order of G, R, and B, and the ratio of each of the RGBs is about 3 as in the Y component of Equation 2. Reacts at a ratio of 6: 1.

4 is a diagram illustrating a mapping table in consideration of human color recognition characteristics according to an embodiment of the present invention. Reference numeral 400 is a chart in which RGB colors are represented by numbers from 0 to 255, respectively. Also, reference numeral 402 denotes a diagram mapped through the mapping table for representing RGB as R (7 bit), G (8 bit), and B (6 bit), respectively.

When the gamut mapping table is applied to FIG. 4, the ratio of RGB to 3: 6: 1 is determined according to the human color perception characteristic as shown in the Y value during the process of converting the RGB of Equation 1 into the YUV method. do. That is, G value should have 8Bit table without changing the size of original data. The R value is assigned to 7Bit, which is half of the G value, and the B value is assigned to 6Bit. This is an allocation value considering that human eyes are most likely to perceive green if the same amount of data changes. And for the same amount of data change, red is easier to notice than blue, and less noticeable than green.

The present invention constructs a gamut mapping table using human perceptual characteristics. Of course, the actual implementation of the mobile terminal should not only determine the ratio in proportion to the human perceptual characteristics, but also take into account the characteristics of the display device of each terminal. Therefore, depending on the characteristics of the device to be implemented using the mapping table, the RGB components of the mapping table are respectively 7bit: 8bit: 6bit (128 × 256 × 64) or 6bit: 8bit: 6bit (64 × 256 × 64). It is possible to apply. In this case, the size of the mapping table is about 2 million and about 1 million, respectively. In both cases, it can be seen that the size is significantly reduced compared to the existing 16 million gamut mapping table.

Therefore, the color image can be expressed even if the size of the memory that stores the mapping table is not large. In other words, by using this method, there are many benefits in terms of hardware without any influence on the part of human perception of color.

In consideration of this point, the structure of a mobile communication terminal embodying the present invention will be described with reference to the accompanying drawings. FIG. 5 is a block diagram for improving an image display method and apparatus configured according to an exemplary embodiment of the present invention. Referring to FIG. 5, the mobile communication terminal includes a color sensor 500, a controller 502, a display 504, a memory 506, a keypad 508, an antenna 510, and an RF module. module 512, baseband processor 514, codec 516, microphone 518, and speaker 520.

The color sensor 500 measures the amount of light and color information of the surroundings, and is referred to as red (R: hereinafter referred to as R), green (hereinafter referred to as G), and blue (hereinafter referred to as B) as three primary colors of light. ) Is distinguished using the difference in color intrinsic wavelength, and the amount is output to the controller 502 as an analog or digital value. This color sensor may or may not exist.

The memory 506 includes a program for controlling a general operation of the mobile communication terminal and a color expression method for dividing the original color image information into luminance components and chroma components according to an embodiment of the present invention. Use to store a mapping table that determines the percentage of the amount of each of the preset color information of red, green, and blue. That is, the memory has a YUV mapping table based on human perceptual characteristics. In addition, when a color sensor exists, a YUV color sensor table based on human perceptual characteristics may be additionally stored.

The controller 502 performs a function of controlling the overall operation of the mobile communication terminal. In the color image processing, the original color image is mapped to color image information corresponding to the original color image according to a mapping table stored in a memory, and the mapped color image information is combined and output to the display unit.

In addition, when the color sensor is present, the controller 502 additionally controls the display unit 504 by a mapping method of the mapping table stored in the memory 506 based on the ambient color information input through the color sensor 500. To provide the user with an optimal image.

The display unit 504 visually displays various signals and color information output from the control unit 502, and the display unit 504 uses a liquid crystal display (LCD).

FIG. 6 is a flowchart illustrating a method of outputting color image data (information) to a display unit using a gamut mapping table in consideration of human color recognition characteristics according to an exemplary embodiment of the present invention. FIG. 6 is a flowchart illustrating a method in which the controller 502 maps color information of an original image to a display unit 504 by mapping the color information of an original image through a gamut mapping table in consideration of human color recognition characteristics stored in a memory 506. to be.

In step 600, the controller 502 checks whether there is an image to be output to the display unit 504 of the mobile terminal by the user. If there is an image to be output to the display unit 504 as a result of the inspection, in step 602, the control unit 502 performs an R of each image to be output to the display unit 504 through a gamut mapping table stored in the memory 506. Maps G, B. In one embodiment, the RGB of the mapping table has a data size of about 2M when 7 bits: 8 bits: 6 bits (128 × 256 × 64) are configured.

In step 606, the control unit 302 combines the R, G, and B values mapped by the mapping table, and in step 608, the control unit 502 outputs the combined result value to the display unit 504 to provide a human. The color image is provided to the user using a small gamut mapping table without changing the perceived color information.

7 is a flowchart illustrating a method of outputting image data to a display unit using a gamut mapping table and a color sensor mapping table in consideration of human color recognition characteristics in a mobile communication terminal having a color sensor according to an exemplary embodiment of the present invention. 7 is a flowchart illustrating a method in which the controller 502 of the present invention changes the color information of the original image according to the surrounding color information and outputs it to the display unit 504.

It is necessary to measure the change in the color information and the amount of light in consideration of the surrounding environment and display the original image in consideration of the change. Methods and apparatus according to these needs are described in patent application 2004-65819 (name of the invention: an apparatus for determining the optimal color combination of a display according to the ambient lighting conditions).

Therefore, a mapping table is added to display a color image in consideration of the change of the surrounding environment, and the mapping table is called a color sensor mapping table. The compression method of the gamut mapping table can also be applied to the additional mapping table.

The process considering this case is as follows.

In step 700, the controller 502 checks whether there is an image to be output to the display unit 504 of the mobile terminal by the user. If there is an image to be output to the display unit 504 as a result of the inspection, in step 702, the control unit 502 may output R of each image to be output to the display unit 504 through a gamut mapping table stored in the memory 506. Maps G, B. As an example, the RGB of the gamut mapping table may consist of 7bit: 8bit: 6bit (128 × 256 × 64), respectively. In this case, the gamut mapping table has a data size of about 2M.

In step 704, the controller 502 receives color information separated by R, G, and B from the color sensor 500. In step 706, the control unit 502 generates RGB images of 7bit, 8bit, and 6bit, respectively, based on the color information received from the color sensor 500 in consideration of the surrounding environment. Each R, G, B is mapped through a color sensor mapping table compressed at (128x256x64).

In step 708, the control unit 502 combines the R, G, and B values output by the color sensor mapping table. In step 710, the control unit 502 displays the combined result value on the display unit 504. Output it to the user with the desired image.

FIG. 7 is a view illustrating a method of compressing a mapping table required when mapping based on a value obtained through a color sensor in consideration of color perception characteristics (visual cell characteristics) in a color image display method considering a surrounding environment. Indicates.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, the present invention provides a structure of an improved mapping table in consideration of human color recognition characteristics to output color image data (information) to the display unit, thereby using a mapping table having a small amount of data. This makes it possible to implement a color image without a difference in the sensed color information.

In addition, in this way, despite the increase in color image information to be displayed, the color image can be displayed without increasing the memory size, thereby increasing the memory utilization of the mobile communication terminal.

Claims (16)

In the mobile communication terminal, Gamut mapping table that sets the ratio of the amount of each color information of red, green, and blue which is set in advance by considering the color perception characteristics of human color which are most sensitive to the green component among red, green, and blue. A memory for storing the; A controller configured to map the original color image to color image information corresponding to the original color image of the gamut mapping table, and output the combined color image information to the following display unit; And And a display unit for visually displaying the combined color image information. The method of claim 1, And a ratio of the amount of each color information of red, green, and blue of the Gamut mapping table is 3: 6: 1. The method of claim 1, And red, green and blue color information of the Gamut mapping table is expressed and compressed in 7-bit, 8-bit, and 6-bit, respectively. The method of claim 1, And red, green, and blue color information of the Gamut mapping table represented by 6bit, 8bit, and 6bit, respectively, and compressed. In the mobile communication terminal, A color sensor measuring color information and light quantity of the surrounding environment; Gamut mapping table that sets the ratio of the amount of each color information of red, green, and blue which is set in advance by considering the color perception characteristics of human color which are most sensitive to the green component among red, green, and blue. Color perception characteristic of human being most sensitive to green component among red, green and blue based on gamut mapping table based on gamut mapping table based on color information and light quantity information of the surrounding environment output from the color sensor A memory configured to store a color sensor mapping table for determining a ratio of the amount of each color information of red, green, and blue which is set in advance; Mapping the original color image to color image information corresponding to the original image of the gamut table, mapping the color image information to gamut mapped color image information according to the gamut mapping table of a color sensor mapping table, and A controller which combines the mapped color image information and outputs the combined color image information to a display unit; And a display unit for visually displaying the combined color image information. The method of claim 5, And a ratio of the amount of each color information of red, green, and blue in the gamut mapping table or the color sensor mapping table is 3: 6: 1. The method of claim 5, And red, green, and blue color information of the gamut mapping table or the color sensor mapping table is compressed by expressing each of 7bit, 8bit, and 6bit. The method of claim 5, And compressing each color information of red, green, and blue of the gamut mapping table or the color sensor mapping table by expressing them as 6 bits, 8 bits, and 6 bits, respectively. In the color image display method of the mobile communication terminal, Setting a ratio of a predetermined amount of each color information of red, green, and blue in consideration of color perception characteristics in which the human body perceives the green component among red, green, and blue most sensitively to the original color image information; Mapping the original color image to color image information corresponding to the original color image, and outputting a combination of the mapped color image information; And visually displaying the combined color image information. The method of claim 9, In the step of setting the ratio of the amount of each color information of red, green, and blue of the Gamut 양 mapping table, the ratio of the amount of each color information is 3: 6: 1 Way. The method of claim 9, Color image display of the mobile communication terminal, characterized in that by setting the ratio of the amount of red, green, blue amount of the Gamut mapping table by expressing each color information as 7bit, 8bit, 6bit respectively Way. The method of claim 9, Color image display of the mobile communication terminal, characterized in that by setting the ratio of the red, green, blue amount of the gamut mapping table by expressing each color information as 6bit, 8bit, 6bit respectively Way. In the mobile communication terminal, A color sensing step of measuring color information and light quantity of the surrounding environment; Gamut mapping table that sets the ratio of the amount of each color information of red, green, and blue which is set in advance by considering the color perception characteristics of human color which are most sensitive to the green component among red, green, and blue. Setting step; Based on the color information and the light quantity information of the surrounding environment output from the color sensor, the color perception characteristic of the human being most sensitive to the green component among the red, green, and blue color gamut mapped image color information according to the gamut mapping table. A color sensor mapping table setting step of determining a ratio of the amount of each color information of red, green, and blue which is preset in consideration; Mapping the original color image to color image information corresponding to the original image set in the upper gamut mapping table setting step, and gamut mapping color image information according to the gamut mapping table set in the color sensor mapping table setting step Mapping to color image information corresponding to and combining the mapped color image information; And And visually displaying the combined color image information. The method of claim 13, Wherein the ratio of the amount of each color information is 3: 6: 1 in setting the ratio of the amount of each color information of red, green, and blue of the gamut mapping table or the color sensor mapping map. How to display color image of communication terminal. The method of claim 13, In the step of setting the ratio of the amount of red, green, blue of the gamut mapping table or the color sensor map mapping table, each color information is represented by 7bit, 8bit, 6bit, and compressing and setting How to display color image of communication terminal. The method of claim 13, In the step of setting the ratio of the amount of red, green, and blue of the Gamut mapping table or the color sensor mapping map, each color information is represented by 6bit, 8bit, 6bit, and compressing and setting How to display color image of communication terminal.

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